1. Field of the Invention
This invention relates to a dual system brake control valve for an automotive vehicle which includes two brake fluid pressure systems or circuits to be controlled, and more particularly to a dual system brake control valve for an automotive vehicle in which, for example, a right front wheel and a left rear wheel are braked with one of the X-type two brake fluid pressure circuits, while a left front wheel and a right rear wheel are braked with another of the X-type two brake fluid pressure circuits, and in which the brake fluid pressure to both of the rear wheels is controlled.
2. Description of the Prior Art
Generally, a brake control valve of such a kind includes two separate control units independent on each other for the brake fluid pressure circuits. It is required for the brake control valve that the fluid pressures to be supplied to the rear wheels should be so controlled with the control parts as to be equal to each other in the two brake fluid pressure circuits.
When one of the two brake fluid pressure circuits is out of order, and no fluid pressure occurs in the one brake fluid pressure circuit, the vehicle should be braked only with another of the two brake fluid pressure circuits. In such a case, the fluid pressure should be so controlled with the control part as to be further higher in the other brake fluid pressure circuit than the fluid pressure when both of the two brake fluid pressure circuits are in order, or normal.